example(1, mammal,   [has_covering=hair,     milk=t, homeothermic=t, habitat=land, eggs=f, gills=f]).
example(2, mammal,   [has_covering=none,     milk=t, homeothermic=t, habitat=sea,  eggs=f, gills=f]).
example(7, reptile,  [has_covering=scales,   milk=f, homeothermic=f, habitat=sea,  eggs=t, gills=f]).
example(9, bird,     [has_covering=feathers, milk=f, homeothermic=t, habitat=land, eggs=t, gills=f]).